Sightron SIII 8x32 ED Details

Sightron SIII 8x32 ED Specifications

Manufacturer

Sightron

SKU

793139-251633

Binoculars series

Sightron SIII ED

Prism type

Introduction

Most modern binoculars are made with an element called prism which is responsible for the rotation of the image upright as the viewer sees it. Prism in binoculars also determines their size, shape, optical features and plays an important part in providing image quality of binoculars. However, prism is the most neglected factor in the process of buying binoculars. There are many types of prisms present which normally determine the purpose of a certain binoculars – whether they are for hunting, marine, bird watching etc.

Source: Lovec

Porro Prism Binoculars

Binoculars that contains Porro prism (named after Italian physic Ignazio Porro) in their optical construction were predominantly the first type of binoculars on the market. In the last couple of decades, binoculars with Roof prisms (either Schmidt-Pechan or Abbe- Köning) became more popular, due to their compactness and water-tightness. This traditional arrangement of binoculars provided by Porro-prisms makes objective lenses further apart and thus offering a higher light transmission rate. Images are not only brighter and sharper but also have a better depth of field, offering realistic 3D images and wider field of view. Many Porro prism binoculars have also focusing mechanism separated for each eye, which can be very useful in low-light situations, when observing at dusk and at dawn. Even though Porro prism binoculars are becoming rare in today’s times, this traditional arrangement makes them more affordable due to less expensive manufacturing. But wider design makes them heavier and difficult to hold in hands and they are less watertight and also less rugged, providing a less secure grip. The other disadvantage of Porro prism binoculars is also the lack of adjustable eyepieces, which in most cases leads to problems when using the binoculars with glasses.

Features of Porro Prism Binoculars

(+) higher light transmission rate

(+) better depth of view perception

(+) wider field of view

(+) realistic 3D images

(+) lower price for high-end binoculars

(-) heavy and clumsy

(-) less watertight

Abbe/Koenig Roof Prism Binoculars

Binoculars with roof-like prisms in their optical construction provide compact design due to straight-line position of eyepieces and objective lenses. They are more expensive due to complex manufacturing and are providing many advantages for more demanding users. They are less sensitive to impacts and abrasions and are incredibly impervious for water and dust entering the construction. They are usually purged with nitrogen or argon gas, which also helps to eliminate internal glass fogging. Compared to Porro prism binoculars, they are more likely to withstand extreme weather conditions. Very good ergonomic design of this straight-line construction makes them less difficult to hold in hands and eases your portability immensely. But compared to Porro prism binoculars, this construction makes light transmission less permeable and thus providing darker and less sharp images.

Roof prism binoculars are divided in two main groups with the following types of prisms:

Roof prism binoculars according to the types of prisms

1. Schmidt – Pechan

(+) compact

(+) lightweight

(+) good ergonomics

(+) easy handling

(+) central focusing

(+) waterproof

(+) adjustable eyepieces

(-) lower light transmission rate compared to Abbe-König

2. Abbe – König

(+) compact

(+) better light transmission

(+) easy handling

(+) central focusing

(+) waterproof

(+) adjustable eyepieces

(-) expensive

(-) longer design

The main difference between both types of binoculars with Roof prism is that those with Schmidt – Pechan prisms tend to be smaller and less expensive, while those with Abbe – Köning prisms tend to have better light transmission rate and have a longer design.

Schmidt/Pechan Roof Prism Binoculars

Binoculars with roof-like prisms in their optical construction provide compact design due to straight-line position of eyepieces and objective lenses. They are more expensive due to complex manufacturing and are providing many advantages for more demanding users. They are less sensitive to impacts and abrasions and are incredibly impervious for water and dust entering the construction. They are usually purged with nitrogen or argon gas, which also helps to eliminate internal glass fogging. Compared to Porro prism binoculars, they are more likely to withstand extreme weather conditions. Very good ergonomic design of this straight-line construction makes them less difficult to hold in hands and eases your portability immensely. But compared to Porro prism binoculars, this construction makes light transmission less permeable and thus providing darker and less sharp images.

Roof prism binoculars are divided in two main groups with the following types of prisms:

Roof prism binoculars according to the types of prisms

1. Schmidt – Pechan

(+) compact

(+) lightweight

(+) good ergonomics

(+) easy handling

(+) central focusing

(+) waterproof

(+) adjustable eyepieces

(-) lower light transmission rate compared to Abbe-König

2. Abbe – König

(+) compact

(+) better light transmission

(+) easy handling

(+) central focusing

(+) waterproof

(+) adjustable eyepieces

(-) expensive

(-) longer design

The main difference between both types of binoculars with Roof prism is that those with Schmidt – Pechan prisms tend to be smaller and less expensive, while those with Abbe – Köning prisms tend to have better light transmission rate and have a longer design.

Roof - Schmidt/Pechan

Variable magnification

Variable magnification

Optical products with variable magnification are more versatile as they're designed with a wider range of magnification and larger viewing angle. With their high number of lenses in housing, optics with variable magnification are larger, heavier and have lower permeability of light. Variable magnification is rarely present in binoculars, but it's mostly used in riflescopes and spotting scopes. Advantages of the variable magnification regarding usability with riflescopes and spotting scopes outweigh disadvantages – in short one fits all. High quality variable binoculars are very rare.

No

Magnification

Introduction

Magnification is an optical parameter which enlarges/zooms the viewing image and makes the observed object seem bigger. For example, with magnification factor 10 we see objects 10 times larger, which means if an object is 0.1 m high and 100 m away we see it 1 m large. In other words, it’s the same observing the object that's 100 meters away with a 10x binoculars as watching it with the naked eye 10 meters away. In choosing the right magnification for fixed magnification optical products, practice shows that the most useful magnifications are between 7x and 10x, where average people seem to handle optics without too much hand tremor.

Source: ZEISS

Fixed magnification

Optical products with fixed magnification are designed in a way that they allow only one magnification of a viewing object. Due to a smaller number of lenses used in their construction, they are optically brighter and have lower loss of brightness. The number of lenses contributes to its smaller size and lighter weight in comparison to optics with variable magnification. Most of binoculars tend to have fixed magnification, whereas with riflescopes it’s getting rarer each year. Normally this kind of optical products are easier to use and cheaper. They also offer better optical performance, especially in terms of light transmission rate.

Variable magnification

Variable magnification simply means that the optical product is designed in a way where you can change magnification of a certain area. This consequently changes the viewing angle, where higher magnification means smaller/narrower viewing angle and lower magnification means wider viewing angle. Variable magnification adds to versatility and general usefulness.

8x

Lens diameter

Lens diameter

Lens diameter represents the second value in product’s name/designation. For example, 10x42 optics have 42 mm diameter of the lens at the front (those that are closer to the viewing object). It is known that the bigger the lens, the more light goes through and the image we see is brighter. All of this, however, depends on the magnification and quality of a certain optical product. Although the bigger lens diameter in binoculars is better, the size adds up on the weight, making it more heavy and difficult to handle. With riflescopes, bigger size of a lens diameter also means more problems with mounting.

The most common lens diameters are 24 mm, 42 mm, 50 mm and 56 mm.

Source: ZEISS

32 mm

Exit pupil

Exit pupil

Exit pupil is a circle from which the light is being transferred to your eye through the optical product. When you holdthe optics a bit far away from your eyes towards a light, exit pupil can be seen as a bright circle in the center of each eyepiece. The larger the exit pupil the more light can reach the eye and the image appears brighter. This is why exit pupil plays an important part in the optical products in poor light conditions at dawn or dusk. Size of the exit pupil also determines how comfortable viewing through an optical product really is. An important factor is also the size of the eye box, which is a space where the eye still has an entire picture, without any tunnel vision or blurry edges. Bigger eye box means more flexibility of the eye position and therefore more comfortable viewing, because the eye can move in several directions within the eye box and still obtain a full image.

Source: ZEISS

The diameter of the exit pupil is calculated by dividing lens diameter with magnification. E. g. 8x50 binoculars have an exit pupil in the diameter of 6.25 mm.

To ensure a brighter image, the eye pupil in low light conditions has to be at least as big as the exit pupil. This way there’s no loss of light and the image is as bright as possible. However, the maximum diameter of the eye pupil depends on age. At night, children’s eye pupils can widen up to 7 mm, while with aging they decrease to a maximum of 4 mm. So if the viewer’s pupils can only be open up to 4 mm, the 7 mm exit pupil cannot be fully utilized. It may contribute to more comfortable viewing, but not to brighter image.

Source: ZEISS

In daylight, when the eye pupil is open up to 3 mm, all the optics with exit pupil bigger than 3 mm are equally bright. For example, the 8x30 binoculars with 3.75 mm exit pupil are no brighter than 8x56 binoculars with 7 mm exit pupil. Those with 7 mm are however more comfortable to use, since they’re less sensitive to the eye position (they have bigger eye-box).

4 mm

Eye relief

Eye Relief

The only way of obtaining the whole field of view is to have the right distance between the eye and eyepiece – referred to as the eye relief. The eye relief is not necessarily a decisive factor in choosing the right optical product, however it is a useful information if you wear glasses. The eye relief then should be at least 16 mm for comfortable viewing and getting a complete image. Binoculars with too short eye relief give people with glasses a tunnel vision and only show the middle part of an image. With riflescopes the optimal distance is 90 mm or even more for safety reasons (recoil).

Without glasses the distance when using binoculars should be minimum of 15 mm, although everyone has a preferred placement as long as they’re obtaining complete field of view with no blurry edges.

Most binoculars have movable eyecups, where you can adapt them to fit different face structures (if your eyes are further away from you nose etc.) and therefore maintain a steadier grip. If you wear glasses, the eyecups should be closed down so you can lean them onto your glasses.

Source: ZEISS

17 mm

Field of view

Field of view

Field of view is an area you see when looking through the optical product. Although it primarily depends on the build of the eyepiece, it is hugely affected by magnification. If you look through two binoculars of the same model but with different magnification, you can see that the one with lower magnification factor will have a wider field of view. So when comparing binoculars, you must compare the ones with the same magnification. With riflescopes the field of view is being measured at 100 m, while with binoculars, spotting scopes and other optical products it's measured at 1000 m.

With binoculars a field of view with more than 140 m at 1000 m distance is considered a wide angle, while with riflescopes it is with a field of view over 38 m at 100 m. Wide angle is particularly useful in bird-watching.

It is also important to mention that the size and lens diameter of optical products are not indicators of their field of view - bigger housing doesn’t automatically mean wider field of view.

Field of view can be expressed in two values – degrees or meters.

Degrees:

One degree is 17.5 m at 1000 m / 1.75 m at 100 m.

If you divide the field of view given in meters by 17.5 you get the field of view in degrees.

Meters:

If you multiply degrees with 17.5 you get the field of view at 1000m.

Source: Lovec

120 m/1000 m

Field of view (deg.)

Field of view

Field of view is an area you see when looking through the optical product. Although it primarily depends on the build of the eyepiece, it is hugely affected by magnification. If you look through two binoculars of the same model but with different magnification, you can see that the one with lower magnification factor will have a wider field of view. So when comparing binoculars, you must compare the ones with the same magnification. With riflescopes the field of view is being measured at 100 m, while with binoculars, spotting scopes and other optical products it's measured at 1000 m.

With binoculars a field of view with more than 140 m at 1000 m distance is considered a wide angle, while with riflescopes it is with a field of view over 38 m at 100 m. Wide angle is particularly useful in bird-watching.

It is also important to mention that the size and lens diameter of optical products are not indicators of their field of view - bigger housing doesn’t automatically mean wider field of view.

Field of view can be expressed in two values – degrees or meters.

Degrees:

One degree is 17.5 m at 1000 m / 1.75 m at 100 m.

If you divide the field of view given in meters by 17.5 you get the field of view in degrees.

Meters:

If you multiply degrees with 17.5 you get the field of view at 1000m.

Source: Lovec

-

Apparent field of view (deg.)

Apparent field of view (deg.)

The apparent field of view is a value in degrees that represents the viewing angle of an image you see through the eyepiece. Two binoculars that share the same magnification, lens diameter and field of view don’t necessarily have the same apparent field of view, because it depends on the structure of the lenses inside an eyepiece. It’s simply a subjective impression of the field of view.

Apparent field of view is also depending on the eye relief distance. Shorter eye relief means wider apparent field of view. But if comparing two different binoculars with the same eye relief, the one with the larger eye lens in the eyepiece will have larger viewer field.

It can be calculated by multiplying the actual field of view with the scope’s magnification. Higher value is better as it makes the image appear wider and bigger.

Source: Nikon

-

Close focus

Closest focus distance

Closest focus distance is an important value when watching butterflies, moths or plants at a really close distance. It represents the nearest distance where the viewing object can still be in focus. With binoculars, an excellent viewing distance is from 1.5 m below. If you’re not particularly interested in watching objects at a close range this is an irrelevant factor when choosing a new pair.

-

Twilight Factor

Twilight Factor

In the past, twilight factor was an important value in determining the brightness of the optics. The manufacturers were using the same kind of technology and materials of the lenses therefore the optics were comparable. Nowadays, they use different types of lenses and modern coatings so the twilight factor has lost its meaning, because the brightness of the optics depends more on the quality of the coatings than on the twilight factor.

Twilight factor is calculated by the square root of multiplying magnification and lens diameter.

Twilight factor of 8x42 binoculars is a square root of 336, meaning 18.33. All the binoculars with this kind of magnification and lens diameter have the same twilight factor, but not the same brightness. If you look through an old pair of binoculars made in 1950s and a new pair with the same magnification and lens diameter you could see the difference in brightness even though they share the same twilight factor. The new pair is significantly brighter due to better lens materials and coatings.

Though manufacturers still specify the twilight factor, we recommend you to ignore it as it’s not important.

-

Relative Brightness

Relative Brightness

Relative brightness is a calculation of how bright the image should be when viewed through binoculars. It is presented as a square value of the exit pupil. 10x50 binoculars have an exit pupil value of 5.0 (dividing lens diameter with magnification). Square of 5.0 gives us a value of relative brightness which is 25.0. As the relative brightness value increases, we have a brighter image. On the opposite the lower the value, the darker the image.

Relative brightness has lost its meaning, because the brightness primarily depends more on the quality of optical products.

-

Light transmission

Light transmission

Light transmission specifies an amount of light that is let through the build of optical product. Every crossing through each lens means a certain loss of light (0.1% with best coatings, up to 5% without coatings). Higher light transmission rate is very important when using optics at dawn or twilight. Good optics normally have light transmission up to 90%, whereas top-notch ones have 95% light let through.

Although the quantity of light reaching the eye depends on the size of an exit pupil, light transmission determines transparency of the lenses, whether the image is dark and cloudy or bright and clear.

Light transmission can be increased with applying different coatings on the glass surfaces. However, it depends on the coating type and number of layers. Multi-layered coatings mean higher light transmission.

Lens coating

Optical products have many lenses in their housing. With each lens about 5% of the light passing through is lost. This can be solved with an application of coatings on the glass surfaces. With years the technology of coatings changed. At first they used only one layer, where the reduction of the loss was to 2% per surface. Today they use multiple layers of coatings where there’s minimal loss of light - 0.1% per surface. The best binoculars have even 95% of the light transmitted to the eye, through all their lenses.

With increasing transmission of the light, the coating is also important as a protectant of the optical glass and to ensure the true color fidelity, so the colors when entering are the same when exiting binoculars/riflescope. Above all, coatings also increase the image quality because all the light bouncing around on the inside can cover up detail and blur colors.

Source: ZEISS

The process of applying coatings has to be precise, otherwise it can contribute to hazy and blurred image. They must be spread evenly and thinly to ensure the best quality. The better the coatings, the more expensive the optical product.

Lens coatings are as important as the quality of the lenses themselves. You can easily check whether your optical product has coatings – if you look at the reflection and it shows multiple colors such as purple, green or yellow the lenses are definitely coated. On the opposite, lenses with no coatings have a clear reflection without showing any colors.

There are many different ways of applying lens coatings:

Coated: where one or more glass surfaces are coated with one thin anti-reflective layer.

Fully coated: where all glass surfaces are coated in one thin anti-reflective layer.

Multicoated: where one or more glass surfaces are coated in multiple layers. Light transmission is more than 75%.

Fully multicoated: where all glass surfaces are coated in multiple layers. Light transmission is more than 85%.

Outer surface coating: coating on the outer glass surface which protects the lens from external dew (especially in the winter), partially from dirt and other impurities. They can have different names, depending on the manufacturer (LotuTec, Swarodur, AquaDura)

Diopter range is an adjustment on optical products which can correct the prescription on each of your eyes. That way you can see a sharp image without wearing glasses. The diopter ring is normally located on the eyepiece and by turning it your image appears sharper.

Every optical product has different diopter range, from positive (+) to negative (-).

Diopter range in binoculars

The diopter ring is present in central focusing system on each of the barrels near the eyepiece, where you can correct the difference in the prescription of the left and right eye individually. Once you have set the right value, you can focus the image with using just the central focusing ring. If you’re wearing glasses, the diopter value should be set to 0, because the differences in your eyes are already corrected in your glasses.

To see a sharp image without wearing glasses you can easily set the diopter by looking with bare eye, turning the ring and adjusting sharpness. So when looking with both eyes your image should appear sharp. If you have astigmatism the diopter adjustment cannot correct it – you’ll still need your glasses and diopter set to 0 to see sharp images.

Source:Nikon

-

Focusing system

Focusing system

Depending on the purpose of use, there are two focusing systems available in binoculars. Most common is central focusing system, which is almost without an exception present in every roof prism binoculars. The other, less occurring system, is an individual eyepiece focusing, which is most useful in marine (because of the water resistance) and extreme low light situations. Binoculars with this kind of focusing system have an advantage in setting the right focus only once for each eye, which is especially useful when viewing in the dark where it’s not necessary to set the focus again.

With central focusing, it’s often difficult to focus the image in the dark, because there is not enough light to see whether the object is sharp or not.

Binoculars with central focusing

Binoculars with central focusing have a central wheel that is able to provide perfectly sharp images. With central focus knob you adjust the focus of both barrels at the same time, moving lenses simultaneously. When choosing between binoculars with central focusing system it’s important to look for its design and performance. Depending on manufacturer, some binoculars provide sturdier focusing and some very smooth focusing, which is especially suitable for dynamic situations. Focusing throw also varies from binos to binos, it takes more time for setting a proper focus with very long focusing throw, than with the ones with shorter one. When it comes to ergonomic design, most of binoculars provide a central knob with different bulges for a better grip, very convenient when wearing gloves. Since central focusing wheel doesn’t eliminate differences in both eyes, diopter on upper side of the barrel is included.

Features of binoculars with central focusing:

(+) focusing by central focus wheel and diopter

(+) precise focusing

(+) more common

(-) sometimes not fully waterproof

Binoculars with individual focusing

Individual focusing system provides focusing by each eye separately. On the upper side of the both barrels lie focusing rings – diopters, with the numbers for setting a proper focus by moving lenses individually. Majority of binoculars uses the central rotating knob, so this arrangement is not that frequent and most commonly found on Porro prism binoculars. Individually focusing system has many different commercial names like sport auto focus, permanent focus or simply auto focus. The main characteristic of this system is that you can set them only once and afterwards the eyes focus to different distances by themselves. This can be a significant advantage in low-light situations when there is not enough light for precise focusing with central knob. Binoculars of this type are also incredibly watertight and thus very likely to appear on majority of marine binoculars. There are however, some disadvantages of such focusing system compared to more conventional central focusing. Close focusing distance is usually bigger and majority of binoculars with individual focusing does not offer adjustable eyepieces for those wearing eyeglasses.

Features of binoculars with individual focusing

(+) focusing by each eye separately

(+) less common

(+) suitable for marine applications

(+) suitable when focusing in low-light conditions

(+) incredibly watertight

(-) bigger close focusing distance

(-) less convenient for glass wearers

Central

Filled with

Filled with

Optical products are often filled with dry gas to prevent the condensation on the inside of the housing when exposing them to temperature extremes. If there is even a slight sign of air inside, there is a certain % of moisture present. Usually they’re filled with either argon or nitrogen gas, which have the same effect – to prevent the moisture and internal fogging without affecting the optical properties. In addition, these gases also prevent the formation of fungus which would destroy the optics. Internal dewing was the biggest problem in older binoculars when exposed to lower temperatures, because they weren’t watertight and contained air. Newer binoculars are therefore all airtight and filled with dry nitrogen or argon.

Nitrogen

Waterproof

Waterproof

Waterproof feature is made to keep the optical products sealed and protected from water or dust. Such products are suitable for marine, hunting, hiking or in extreme humidity. Even if you’re not planning on using them in this kind of situations, it is a good feature to have in case of heavy rain or dust. Waterproof optical products are typically sealed with O-rings.

All optical products that are fogproof are also waterproof, because they have to be properly sealed to keep the dry gas inside. Yet not all waterproof products are fogproof as the air inside the barrels is not necessarily replaced with dry nitrogen or argon.

You should be careful not to confuse waterproof with weather-resistant as they’re designed to protect only against light rain and are not fully sealed.

Slightly better waterproofing of binoculars can also be ensured with an individual eye focusing mechanism, due to less moving parts than with the central focusing system.

Yes

Fogproof

Fogproof

Fogging in optical products can occur when you move them from the warm insides of your house to the cold outdoors. To prevent the formation of inside fogging they’re often filled with dry gas – either nitrogen or argon which contain no moisture.

To keep the gas intact on the inside, the optics have to be properly sealed, which is why all fogproof optical products are also waterproof.

It’s important to keep in mind that fogproof means that it’s to prevent fogging on the inside of the optics, not on the outside. If your outside surface of the lenses fogs up due to temperature differences or humidity just allow them to adjust back – do not wipe the condensation off as it can be damaging to the glass surface and its coatings.

Yes

Floatable

Floatable

Floatable option is sensible only when using binoculars on the water as there’s a chance they fall into the water and begin to sink. To avoid that most marine binoculars come with a floatable strap, which prevents such accidents. Although rarely, some of them are floatable by themselves.

Source: Steiner

No

Temperature range

-

Built-in rangefinder

No

Compass

Compass

Built in compass is intended almost exclusively for marine use. There are two types available. First one has a digital display of compass in the middle of the field of view. The second, most common compass system is permanently seen at the bottom. They can also be illuminated or not.

Compass showing permanently in the viewing field (left) and compass with digital display at the middle (right)Source: Minox and Steiner

No

Image stabilizer

Image stabilizer

The same as compass, image stabilizer feature is most practical when using in marine, but also useful on moving cars or helicopters. It’s a mechanism that eliminates hand tremor and shakes to secure a stable image viewing. It’s like fixing a tripod under optical product without actually using it. Image stabilization is also useful when featured in hand-held optics with higher magnifications.

The only downside is the price which is several times greater than with optics without stabilization.

No

Color

Black

Length

120 mm

Width

-

Height

No

Interpupillary distance

Interpupillary distance

The distance between each of an individual’s eyes or better pupils is called interpupillary distance. Most binoculars have an option of adapting the barrels to a specific position to ensure the whole image, either bringing them closer together or further apart. Normally this distance is somewhere between 58 and 75 mm. Often women and children have shorter interpupillary distances, so they must choose between compact binoculars.

The best practice is to try binoculars in person to get the feel of them and see if they suit you.